1. Field
One embodiment of the invention relates to an information processing apparatus, which separately controls encrypted content and a key used for encrypting content (hereinafter, called a content key), a content control method, and a storage medium.
2. Description of the Related Art
In recent years, secure digital separate delivery (SDSD)-content protection for recordable media (CPRM) has been proposed as an expanded standard of a secure digital (SD) memory card (hereinafter, called an SD card) to realize sharing and protection of digital content (e.g., SDSD-CPRM: Flexible Protection for Digital Content, White Paper, August 2007 (Document 1)). This document separately handles encrypted content and a content key, which have been handled together most times.
Encrypted content and a content key are distributed, or copied through various routes. For example, encrypted content and a content key are stored together in an SD card, or only a content key is stored in an SD card. For using (reproducing) encrypted content, secure means such as authentication of a key and decryption by using cryptographic technology are required, and restrictions are provided. However, encrypted content itself can be freely distributed. This enables sharing of content.
A content key is never distributed to apparatus. For decryption and reproduction of encrypted content, it is necessary to insert an SD card including a content key corresponding to encrypted content into apparatus for reproducing encrypted content. Therefore, the same encrypted content distributed to various devices can be used at various places by carrying an SD card only.
This standard assumes that a content key is collectively controlled, while encrypted content is distributed to two or more devices. However, this standard defines nothing about collective control of the devices, to which encrypted content is distributed, or copied.
A document 2 (Jpn. Pat. Appln. KOKAI Publication No. 2002-163577) describes that a personal computer having encrypted content and a license acquired from a distribution server through the Internet performs check-out for lending the encrypted content and license to a memory card inserted into a cellular phone connected through a USB cable, and performs check-in for returning the lent encrypted content and license.
The SDSD-CPRM standard described in the document 1 does not define the control of a distribution destination, or a copying destination, when encrypted content is distributed through an SD card. The document 2 describes that content and license are distributed together, but does not define separate distribution of content and license.